# Quantification of Bacterial and Drug-Resistant DNA Using dPCR in a Pediatric Patient with CVC-Related Bloodstream Infection

## TL;DR

This case study shows how dPCR can quickly detect bacteria and drug resistance in a pediatric patient with a bloodstream infection, using less blood than traditional methods.

## Contribution

Demonstrates the practical use of dPCR in pediatric catheter-related bloodstream infections with limited blood samples.

## Key findings

- dPCR detected S. epidermidis and mecA genes in 3.5 hours using only 400 µL of blood.
- Results from dPCR aligned with blood culture and clinical outcomes, supporting its reliability.
- dPCR offers faster turnaround and is suitable for pediatric patients with limited blood volume.

## Abstract

Background: Digital polymerase chain reaction (dPCR) is a highly sensitive molecular method that allows rapid detection of bacterial DNA and resistance genes, requiring only a small blood volume. Although not a new technology, its application in pediatric patients with suspected catheter-related bloodstream infection (CRBSI) remains limited. Case presentation: A 16-year-old female, diagnosed with recurrent acute myelogenous leukemia, received re-induction chemotherapy through a peripherally inserted central venous catheter (PICC). The patient developed a fever, and the blood culture (BC) drawn from the PICC was positive for methicillin-resistant S. epidermidis, leading to suspicion of CRBSI. Several antibiotics were used, and the PICC was replaced. Eventually, the fever subsided, and the BC was negative after PICC removal. The levels of S. epidermidis-specific DNA sequences and mecA genes were correlated with the results of the BC and clinical course. Turnaround time was significantly shorter in dPCR (3.5 h) than in the BC (14–21 h); dPCR was performed using only 400 µL of blood. Conclusions: This case highlights the potential of dPCR as a complementary tool to conventional BCs in the management of pediatric CRBSI. dPCR may support rapid decision-making and monitoring of the treatment response, particularly when sample volumes are limited.